Turbo-lag compensation system having an ejector

Abstract

A boost system for an engine is described. In one example, the boost system provides air to an engine cylinder via a converging-diverging valve seat. The system can reduce turbocharger lag during some conditions.

1. A system, comprising:
 an engine having at least a cylinder, the cylinder in communication with an intake manifold; 
 a compression device coupled to said engine and delivering pressurized air to said cylinder; 
 an air delivery nozzle selectively delivering said pressurized air to said cylinder via an intake runner; and 
 a controller adding said pressurized air to said cylinder via said air delivery nozzle and injecting fuel twice during a cylinder cycle in response to an operator tip-in; 
 wherein said pressurized air from said air delivery nozzle is mixed with a subsonic air stream, where said subsonic air stream is from said intake manifold, and where the controller adjusts a spark timing of said engine during said delivery of said pressurized air in response to the operator tip-in. 
 
     
     
       2. The system of  claim 1  further comprising a plurality of nozzles, with at least one nozzle for each cylinder of the engine, wherein each of said plurality of nozzles is an ejector located in said intake manifold. 
     
     
       3. A system, comprising:
 an engine having at least a cylinder with an intake valve configured to cover and uncover an intake opening into the cylinder, the cylinder in communication with an intake manifold; 
 a compression device coupled to said engine; and 
 an air delivery nozzle in communication with said compression device, said compression device delivering pressurized air to said cylinder via said intake opening where said nozzle has a converging-diverging shape so that discharged air is at a supersonic velocity at least under some operating conditions, wherein said nozzle is located in a valve seat, and where said nozzle is an annular nozzle. 
 
     
     
       4. The system of  claim 1  wherein said air delivery nozzle is located in a one-piece valve seat insert located in a cylinder head. 
     
     
       5. The system of  claim 1  wherein said air delivery nozzle is located in a two-piece valve seat insert located in a cylinder head. 
     
     
       6. The system of  claim 1  wherein said air delivery nozzle delivers air during engine starting. 
     
     
       7. The system of  claim 3  wherein said air delivery nozzle delivers air during engine cold starting. 
     
     
       8. The system of  claim 3  wherein said compression device includes a turbocharger, and the system further comprises a controller configured to deliver said pressurized air in response to an accelerator pedal tip-in by an operator. 
     
     
       9. The system of  claim 1  wherein said compression device includes a supercharger. 
     
     
       10. A system, comprising:
 an engine having at least a cylinder with an intake valve configured to cover and uncover an intake opening into the cylinder, the cylinder coupled to an intake manifold; 
 a turbocharger coupled to said engine: 
 a storage reservoir for storing air pressurized by a compressor; 
 an air delivery nozzle configured to deliver said pressurized air to said cylinder via said intake opening, where said nozzle has a converging-diverging shape and is located in a valve seat; 
 a valve to deliver said pressurized air at different pressure levels; and 
 a direct fuel injector coupled to said cylinder. 
 
     
     
       11. The system of  claim 10  wherein said pressurized air is discharged at a supersonic velocity at least under some operating conditions, and is mixed with a subsonic air stream, where said subsonic air stream is from said intake manifold. 
     
     
       12. The system of  claim 11  wherein said nozzle is located in a valve seat insert. 
     
     
       13. The system of  claim 12  wherein said nozzle is located in a one-piece valve seat insert. 
     
     
       14. The system of  claim 12  wherein said nozzle is located in a two-piece valve seat insert. 
     
     
       15. The system of  claim 12  further comprising a controller configured to deliver said pressurized air in response to a tip-in by an operator, and to adjust fuel injected from said injector to compensate for additional air in the cylinder caused by said delivery of pressurized air. 
     
     
       16. The system of  claim 10  further comprising a spark plug in said cylinder. 
     
     
       17. A method for an engine having a turbocharger and an air ejector assembly, comprising:
 delivering supersonic pressurized air to an engine cylinder via a converging-diverging nozzle within the air ejector assembly, in response to a driver tip-in; 
 setting a duration of said delivery of supersonic pressurized air to correspond to an anticipated duration of turbocharger turbo-lag; and 
 performing multiple fuel injections to the cylinder during a cylinder cycle in response to the driver tip-in. 
 
     
     
       18. The method of  claim 17  further comprising estimating an amount of air entering said engine cylinder based on a storage pressure and cylinder pressure. 
     
     
       19. The method of  claim 17  further comprising ending said delivery of pressurized air in response to at least one of depletion of pressurized air storage and spinning up of the turbocharger. 
     
     
       20. The method of  claim 17  further comprising adjusting spark timing of the engine during at least a portion of said duration to reduce a tendency of engine knock. 
     
     
       21. The method of  claim 17  further comprising increasing airflow from an intake manifold to said engine cylinder via the delivery of supersonic pressurized air. 
     
     
       22. The system of  claim 1 , wherein said air delivery nozzle is in communication with said compression device, said compression device delivering pressurized air to said engine cylinder via an intake opening, where said nozzle has a converging-diverging shape so that discharged air is at a supersonic velocity at least under some operating conditions.